A904 No driving anymore

Transmissions and Rear Ends

  1. SixBanger

    SixBanger Well-Known Member

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    After work driving from the highway exit to a dead stop. Wait some time and then want to accelerate. I did hear a snap somewhere in the trans. I can shift from P to 1 with no problem.
    But from that moment the car is to able to move. Also hear a sound (sheepish) coming from the transmission when not in P. Driveshaft fine, engine fine, oil trans full and red(+- 8 months old + filter).
    Last month I did drive the car up to some mountains a couple of times.

    I have take a look on the manual and some forums. I don't have worked on a automatic trans before. But is it possible that the overrunning clutch is broken and cause the problem?

    Thanks!

    a904.PNG
     
  2. Aspen500

    Aspen500 Well-Known Member

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    If the overunning clutch broke, you should still be able to move forward and reverse. In fact, you'd be able to get all 3 gears if you up shifted and downshifted manually. If it jammed, (rollers get wedged due to possibly the outer ring cracking for example) the car won't move. It'll go into gear but act like you have a trans brake. Also, the car won't roll on it's own, even in neutral. Never saw that happen on a TF but have seen it more than once on a Ford 4R100 trans.

    What type of noise do you hear? Is it sort of a buzzing sound, or more metallic? A buzzing sound could be the pump, or the filter came loose and it's sucking air.
     
  3. SixBanger

    SixBanger Well-Known Member

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    Thanks for info Aspen. Sound is not to loud, guess more buzzing than metal. Hope that the filter came loose, also the easiest to check.
     
  4. Aspen500

    Aspen500 Well-Known Member

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    Those were just some possible faults. A buzzing is a good sign of air in the hydraulic system and hope it's something simple (like a loose filter). While you're in there, double check the main control (valve body) attaching fasteners. They should be snug. Not too tight though. The spec is in inch pounds but I don't remember the exact torque off hand.
     
  5. XfbodyX

    XfbodyX Well-Known Member

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    Sounds like the back ring in the case aspen500 mentioned cracked or broke, ive had it happen twice.

    If it did break the ring in the case a good trans shop can still find the bolt in ring, there is a recer term for it but most just call it a case saver because thats what it does but you wont know till its apart.

    When you did your hill climb did you ever let off and then back on it hard?
     
  6. SixBanger

    SixBanger Well-Known Member

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    Video didn't showed the sound well(some noise from 0:08).

    I have removed the oil pan. Filter seen locked on. I have take some pictures while down under. Some little metal on the oil pan.

    Think I have to remove the driveshaft and remove the trans.

    IMG_20190905_194045.jpg

    IMG_20190905_195418.jpg

    IMG_20190905_195426.jpg

    IMG_20190905_195431.jpg
     
    Last edited: Sep 5, 2019
  7. SixBanger

    SixBanger Well-Known Member

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    But first I will check the bolts of the valve body.
     
  8. BudW

    BudW Moderator Staff Member

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    I copied whole pages from my ’77 FSM (Factory Service Manual). I believe your transmission has a lockup torque converter – so some data will be off, but problem you have is not lockup related.

    This is the diagnostic pages. I didn’t print out the hydraulic flow charts – but can if you want them.

    I have worked on more Chrysler automatic transmissions than more people have even seen (that includes the A904 and A727’s). Most things can be done by anyone – except for a few special tools. Most of the PDF files (below) do not apply to you, but I went ahead and printed them off for you anyway.

    Page number 61 (last page) mentions what condition could be what problem. For a “No Drive in any Position” (middle of page) – most of the conditions will be a “pan off” repair (filter is stopped up or fell off, valve body bolts loosened, etc.) so I believe this might be an easier fix (than not) – but you gotta get the transmission pan off to start checking (first). Internal snap rings can break (or pop out of place) but if that happens, you are most likely due for a transmission overhaul to begin with.
    BudW

    Edit: the amount of debris in oil pan is not bad – but I would like to get a better look at the black round transmission pan magnet (it looks a bit odd). It sounds like transmission removal time.
     

    Attached Files:

  9. SixBanger

    SixBanger Well-Known Member

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    Bud great pdf's.

    I have take a look at the valve body, look like the screws are are tightened as they should be. Only did a quick test because it get dark now sooner. Should check bolts at recommend torque also.

    Sure I would upload a picture of the black round transmission pan magnet special. But last time (first time owning this car) i removed the pan and refresh oil and pan, I did saw more metal on the magnet than now. Has to say, before that the trans was leaking some fluid. And did had some rude shifting when oil was to low. But after new rubber gasket it was solved (+-12k km ago). At looking at the trans, it look like it has been removed before (frame connector, shinny casting), but who knows.

    I notice a little crack on the plate of the valve body (indicated in red). But who knows.

    IMG_20190905_195418 - kopie.jpg
    IMG_20190905_195418 - kopie.jpg

    Overrunning clutch seems like okay (I can turn the driveshaft a bit and see it from down under the car).

    So valve body, oil pump or least likely planetary gear broken.
     
  10. Aspen500

    Aspen500 Well-Known Member

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    Hard to tell in the photo of the pan but, are those chunks of metal towards the middle? If so, that's a bad thing. Sort of suspicious about the "sparklies" near the corner, appear to be brass from a thrust washer or bushing. A tiny amount in a high mileage trans is normal if it's never been serviced.

    As I said, buzzing is usually from the pump sucking air and getting cavitated but noises are hard to describe so, if the filter and valve body are secure, it may be something else. What I would call buzzing is like the sound a p.s. pump makes when the fluid is low (or it's sucking air in to the system).
     
    Last edited: Sep 5, 2019
  11. SixBanger

    SixBanger Well-Known Member

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    Sound was indeed more like a low fluid in ps pump.

    Only option is to remove transmission. Tomorrow I can use a lift bridge of a garage here in the village. I have already removed the driveshaft.
     
  12. BudW

    BudW Moderator Staff Member

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    Your pan magnet had an unusual pattern to it. Generally, I see metal flakes that stick up according to the magnetic rings – but not in a pattern of six, shown. Even the pan is a bit cleaner around those 6 marks.
    IMG_20190905_194045m.jpg
    I found this picture on internet which more looks like metal shavings on a round pan magnet normally looks like:
    iuBEBEYAHA.jpg
    Note this is "too much" metal, but I was only trying to give an example of "how" the magnet looks.


    I can’t see the crack.
    That said, those aluminum castings do have areas that can appear to be cracks – so it might be normal. The area with the alleged crack is at is where the accumulator/accumulator spring is at – which works to soften the shifts between 1-2 and 2-3 shifts. If it did have a good-sized crack in that location, the car would still be able to be driven but the 1-2 (or the 2-3) shift would feel lousy.

    I have seen a few broken accumulators, broken accumulator springs and other things like that but I don’t recall any of them making a noise like you describe.

    A teaspoon is about 5.9 ml. A teaspoon of debris in transmission oil pan in about 30k miles (48k km) is normal (in my opinion) if there are no chunks or other “bigger than shavings” pieces present. There is about 4 things in middle of pan I’m concerned about. Not quite chunks but larger than shavings. I’m not excited to see them and a bit concerned – but not to point of condemning anything, just yet. I would “guess” the debris in pan is maybe 1/4th of a teaspoon (including what is on magnet).

    Could you repeat what the transmission is doing again, exactly, and if there is any shifting or other drivability items that wasn’t there previously?
     
  13. SixBanger

    SixBanger Well-Known Member

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    Today pulled out the trans.

    IMG_20190907_130238.jpg


    Clean it. Seen rebuild one. But shiny parts say not much.

    A better picture of the magnet. The metal around the magnet is real small pieces of material. I can see that the bigger shavings on the previous picture are a bit concerned.

    Some pictures of the internal components. I assume there is no big problem with shafts or planetaire gearset. You can rotate the different sessions of the transmission (two clutches houses, in- and out shafts (don't know the right word to describe it)) . I have showed it on the video.



    But this is not saying of the operation of the clutches and other components.
    Bud, do you maybe have in your manual a exploded view of all parts of the a904? I would check the components of the valve body. I am not digging in the clutches etc. Maybe see the pump or test the valve body with compressed air (this is described in the FSM manual Bud sent me).


    IMG_20190907_130252.jpg

    IMG_20190907_163021.jpg

    IMG_20190907_165805.jpg

    IMG_20190907_170335.jpg


    IMG_20190907_170548.jpg

    IMG_20190907_170601.jpg

    [Debits from filter/upper plate valve body, seems not metallic]

    IMG_20190907_170633.jpg

    Now I have a better look on the cracks in the valve body. But if this should only effects the smoothness of shifting, then this is no directly cause.
    To date, it has always smoothed shifting up. With the previous leaking gasket it was only shifting down from 2 to 1 lump, but this has been remedied with a new gasket and leak-free transmission.

    [Crack 1]
    IMG_20190907_170341.jpg

    [Crack 2]
    IMG_20190907_170820.jpg
     
    Last edited: Sep 7, 2019
  14. SixBanger

    SixBanger Well-Known Member

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    Photos

    IMG_20190907_170914.jpg

    IMG_20190907_173206.jpg

    IMG_20190907_174228.jpg


    Before the transmission broke I did not notice any change in driving characteristics or strange noises / vibrations. Always switched on the right times (after my knowledge). For example shifting 2-3, speeds of 50 km/h and small part load, moderate part load 70 km/h and full load 110 km/h for example. Shifting smooth.

    I have to say, in the last month I have driven more than 3000+ miles abroad. Wherever from over mountains (generally quiet driving on steeper roads 2nd gear). No noise or other strange transmission or engine related observations. But after driving 500 miles of the 2nd trip, I drive a on the Nurburgring (visitors round). But was more cruising in part load on the track.
     
  15. Aspen500

    Aspen500 Well-Known Member

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    I think the pattern on the magnet is just caused by the shape of the magnet, with 6 grooves in it. However, in the close up, the amount and type of shavings are concerning. It is normal to have an almost paste like accumulation on the magnet but when it starts looking like a porcupine, that is not normal.

    The "cracks" in the valve body are, as Bud said, just flaws from the die-casting process. At any rate, they wouldn't keep the car from moving.

    Without being there and seeing it in person, I'm leaning towards a mechanical failure of some sort. More disassembly and careful inspection will be needed. If you have a FSM, an auto trans isn't really that hard to take apart and put together (I find it much easier than a manual trans). Having all the special tools helps a lot but it can be done without them, just takes a lot longer and requires more cuss words, lol. To get the clutch assy's apart however, you do need a clutch spring compressor, either store bought or homemade.

    Trying to remember exactly, I've seen the forward planetary (aluminum alloy) have the splines strip out more than once. I honestly don't recall if it only caused a loss of 3rd gear or all gears though. It's been a while.......................:confused:
     
    Last edited: Sep 7, 2019
    SixBanger likes this.
  16. SixBanger

    SixBanger Well-Known Member

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    Okay then I need to dig in more deeper. And looking for some more clean work space.

    For now I would just make a lot of pictures. I have a Haynes repair manual, it is ok with for general maintenance (it give a idea of the procedure before you start the job). But a more detail information would be better.
     
  17. SixBanger

    SixBanger Well-Known Member

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    Here I see 3 gear and reverse. But is this also happend with rear planetary? Or I confuse coupling and planetary gearset with each other.

    Knipsel.PNG

    Found a a904/727 manual online. For a noob in trans like me maybe useful
     
    Last edited: Sep 7, 2019
  18. SixBanger

    SixBanger Well-Known Member

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    Yesterday pull out some parts of the trans.

    I found the output shaft to forward drum washer in the alu bellhousing of the forward planetary gearset. It was bended. There is some axial play in the assembly of the outputshaft. Maybe I can measure the play. Also all trust washers show some wear on the copper side. What I am thinking there was to much play between input and output shafts that the drum washer could come 'free' and so bended and disconnect the bellhousing of the 2nd clutch (input shaft) and 1st gearset (output shaft)?

    All other parts look by so far ok.

    IMG_20190907_231240.jpg

    IMG_20190907_231418.jpg

    IMG_20190907_231920.jpg

    IMG_20190907_232252.jpg

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    IMG_20190908_000722.jpg

    IMG_20190908_000748.jpg

    IMG_20190908_000807.jpg

    IMG_20190908_001707.jpg

    Video of output shaft play and components.

     
    Last edited: Sep 8, 2019
  19. Aspen500

    Aspen500 Well-Known Member

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    Hard to see in the photo's but it looks like something is missing from the front of the output shaft where the now bent thrust washer goes. There should be a pin (like a dowel) on the end of the shaft that the washer goes onto and then into the end of the input shaft, similar to the input of a manual trans going into thepilot bearing of the crankshaft. You say you found the washer laying in the drum, correct? Without that thrust washer, and the dowel to align both shafts, it could very well cause a no drive concern, as you suspect.

    The wear on the larger thrust washers doesn't appear to abnormal. If the end play measurements are in spec, they'll be OK.
     
  20. BudW

    BudW Moderator Staff Member

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    Now that I can see the picture better, this is troubling (that much metal).
    IMG_20190907_165805.jpg

    Things to inspect, while transmission is out:
    Take a bright flashlight and check for any cracks around the six crankshaft bolt holes and around the four torque converter bolt holes. I doubt you have any – but well worth the effort to look before reassembly.
    IMG_20190907_130238m.jpg

    Look for cracks around the torque converter hub at the two machined slots. It is common for the metal hub to crack there. Also, check the smoothness of the hub with your fingernail. It should not catch anything. If your fingernail catches or there is a crack present – replace the converter. If both are good, then take existing converter to a torque converter shop to get flushed out. The converter holds more fluid than rest of transmission and very difficult for most people to even get most fluid out (not counting metal shavings. A converter flush costs about ½ the cost of converter replacement in my area.
    IMG_20190907_130252m.jpg

    With the potential cracks in valve body. Look on other side of the valve body to see if anything can be seen from other side. I suspect nothing is present on other side. If that is correct, then continue on. If there is a crack or is a porous casting, then epoxy (on outside of valve body) might fix it. Either way, I don't think it is much to worry about.
    IMG_20190907_170341m.jpg

    With that much metal present – I do recommend going completely though the transmission, including the valve body.


    For major overhauls, I prefer to use two tables/workbenches. One table to work on and the other table with parts laid out (in order of removal). I also recommend using either a “clean” tarp or plastic to cover your parts with when not actively working on it. Dirt is the huge enemy of automatic transmissions (as well as bugs and other things. Also, I like to have lots of "clean" cardboard on both tables. If you drop something (which happens with wet fingers), the cardboard will prevent damage and soak up some spills. After I remove the different assemblies, I will then rebuild each assembly in order of removal. If in doubt, use a sharpie marker on the cardboard. You can't make enough notes on these things, expecially on your first time. Also, lots and lots of camera pictures is also very helpful.


    When reassembling, I recommend getting a small tub of petroleum jelly. Use some jelly to help hold those bushings and thrust washers in place when going together. The jelly will dissolve in the fluid. Not hurting anything (it is what factory and transmission rebuilders use).
    81eGf01jibL._SL1500_.jpg
    An example. I would use whatever is cheapest.

    Also get a disposable small container large enough to place your new clutch disks into. Those disks are made out of paper and need to soak in ATF for at least an hour before use. Same for the two bands if replacing with new (they don't need to soak as long). Reusing bands or disks, a quick dip in ATF should work fine.

    Look at the overrunning clutch. Using needle-nose pliers, you can remove the springs to look at questionable ones. If all look, OK, then reuse them.
    77 FSM 21-99b.png
    If a problem with one spring is found, replace them all. I don't see much problems with the cam. They can be very difficult to replace if you do have a problem with one.

    Install the front band just before installing the front pump and after installing the two clutch drums. It makes getting the two clutch drums in easier (less fighting with the band). After everything is ready for the front pump to be installed, tighten the front band (snug but not tight) to help hold things together for the pump.

    I do recommend dissembling the front pump to clean out any metal and to check condition of converter hub bushing (and to change the seal). To assemble the front pump, get a pair of longer bolts that fit the threads used for slide hammer (3/8”-16 I think – but don't quote me on that) and cut off the heads to use as pilot studs (or long enough to use as a guide to get pump back together. All-thread can work. The assembling tool might be hard to get your hands on – for it is a rather large diameter. You have a lot of options but having a second pair of hands is very helpful. Use of thin sheet steel, plastic or even an old leather belt works. I prefer to install the two halves together the opposite direction shown (pilot studs pointing down and pump gears already in outermost housing – so the alignment tool wouldn't be needed. A couple blocks of wood is helpful.
    77 FSM 21-86g.png

    Apply a lot of ATF to the (front pump) big square-cut O-ring and to the case before inserting pump.

    The (outer) pump bolts have plated metal washers/seals (see purple circle, three pictures down). I recommend installing the pump, make sure your end play is correct and such, and once happy with all of that, remove the pump bolts and install those seals LAST. Those seals are “wet” and can be under a bit of pressure – so is a potential (and very common) leak area. Those seals will be damaged with constant tightening/loosening/tightening, which is why I install them after any pump business is done.
    Also get a pair of long bolts and cut heads off to use as pilot studs. On these pilot studs, it does help to round the ends as well as slot the ends so a screwdriver can remove them after pump is in place. I addition, it helps to get a pair of (again, I think are 3/8”-16 bolts) of 3 to 5 inch long) to use as handles (in the same holes the slide hammers use) to help hold pump while inserting it
    77 FSM 21-102g.png
    Note: the pilot studs used here (above) will be in same holes as your pair of "handle" bolts will be in (a poor picture).
    77 FSM 21-83g.png
    The "handle" bolt locations.

    When tightening the pump bolts, take it slow and criss-cross the bolts to tighten. At same time, keep checking the input shaft. It should not get hard to turn when tightening bolts. If it does, STOP!. Take the pump off and start to check if any thrust washers fell out of place. It takes a while, but this step has saved a lot of ruined parts, grief and time.

    77 FSM 21-82g.png
    Getting the end play set correctly is important (might be the most important item), even if you have to wait a while to get the correct thickness thrust washer(s).
    It would have been nice to measure the end play before disassembly (which may or might not of happened).

    Continued